Update haskell.nix, remove workarounds (#1154)

input-output-hk/haskell.nix#2218 was merged,
which allows us to remove the workarounds introduced in #1142

Author: amesgen

cabal.project

@@ -36,10 +36,3 @@ import: ./asserts.cabal
 if(os(windows))
   constraints:
     bitvec -simd
-
--- Workaround for a haskell.nix bug around pre-installed libraries. Might be
--- fixed by https://github.com/input-output-hk/haskell.nix/pull/2218.
-extra-packages: Cabal
-if os(windows)
-  constraints: time ^>=1.14
-  allow-newer: *:time